Containers define a different way to host workloads within cloud environments. While there are container orchestration packages, such as DOCKER, DOCKERSWARM, CLOUDIFY, etc., that identify container-based workloads, the orchestration is something that is locally-significant to the orchestration layer and not something that is transported over the network.
Assume the following example container based deployment: Two different HTTP based applications are deployed across a cluster of containers distributed across multiple compute nodes. Each application is running separate from the other (different containers), but can share the same compute node. At the moment, without being able to uniquely identify containers on the same compute node running the same application but offering a different service, there is no way to apply policies or other network functions. IPs, TCP/UDP ports or other HTTP specific distinguishers are not sufficient to separate containers on the same compute node (or across compute nodes) and identify them on the network.